menu on right click on canvas

greetings,
i want to have a contect menu over canvas and its items. This items wil contain the operation i want to perform over it.
I have gone throught doc there is contextMenuEvent() for qwidget but nothing such for QCanvas. How i can code such functionality.

quickNitin

Like I just said in the overlapping canvases thread,

Quote:

---

Well, Q3Canvas isn't a widget and can't be displayed on its own. You're displaying the canvas in a Q3CanvasView, right? Q3CanvasView is a widget and can be moved, resized, etc. like any other widget.

---

The same applies in this. You are supposed to handle the context menu event for Q3CanvasView, not the Q3Canvas.

i tried and menu did worked.
I need some advice on how to proceed further.
As we discussed in thread http://www.qtcentre.org/forum/f-newb...ases-3928.html
, i have a large canvas , over this i have many canvs elements and some other smallcanvas. Now i want this context menu to be specific to element on which it is clicked.I mean i have diffrent function corresponding to diffrent element. These operation includes , changing elements shape and displayig information(selective) about that element.

if i do this, this is generating a general context menu, orignating same at each place irrespective of click where it happenend or i can get position from QContextMenuEvent class.

Code:

---

...
	abc=new QAction(tr("hello"),this);
	connect(abc,SIGNAL(triggered()),this,SLOT(ABC()));
...
 	void ABC()
	{
		QMessageBox::information(this,tr("Hello"),tr("Sample Context Menu Acion"));
 
	}
...
void contextMenuEvent(QContextMenuEvent *event)
 	{
 	 	QMenu mn(this);
 		mn.addAction(abc);
 		mn.exec(event->globalPos());
 
 	}

---

same here

Code:

---

void contentsMousePressEvent( QMouseEvent *e )
   {
     Q3CanvasItemList il = canvas()->collisions( e->pos() );
     if(e->button()==Qt::LeftButton)
	{   
	for( Q3CanvasItemList::Iterator it=il.begin(); it!=il.end(); ++it )      {
       	if( (*it)->rtti() != Q3CanvasText::RTTI )
       	{
         dragging = (*it);
 
         xoffset = (int)(e->x() - dragging->x());
         yoffset = (int)(e->y() - dragging->y());
 
         return;
       }
      }
     }
	else if(e->button()==Qt::RightButton)
	{
	 for( Q3CanvasItemList::Iterator it=il.begin(); it!=il.end(); ++it )      {
       		if( (*it)->rtti() != Q3CanvasText::RTTI )
       		{		
			if( (*it)->rtti() == Q3CanvasRectangle::RTTI)
			{ 
			QMessageBox::information(this,tr("Hello"),tr("Sample Context Menu Acion on rectangle"));
			//[COLOR="Red"]can generate a specific menu here but how will pass this canvas element to that action for operations over that[/COLOR]
			}
		}
		}
	}
   }

---

i know on which element i clicked but how i can pass this information( on which object on canvas or window i clicked ) to actions on context menu. Why i need context menu is since i have 5-6 oprns. User will select between them.

all advices are welcome in this regard as i am getting very raw ideas(working on such task for first time).

Maybe you could just simply store the item as a member variable? Or use QAction::setData() for storing a pointer to the item. It's totally up to you how do you want to implement it. It might also depend on which slots and where do the actions trigger..

i am getting some feel of it.
Ihave declared a member variable Q3canvasitem class pointer.in contentsMousePressEvents() i am checking rtti() of canvas item( obatained through collision) .There i am storing corresponding item in member pointer and generating menu there only.
With other development i will keep updating.